Intercellular signaling regulates a variety of important biological functions. For example, transforming growth factor type beta (TGF-β) regulates the proliferation and differentiation of a variety of cell types binding to and activating cell surface receptors which possess serine-threonine kinase activity. Atfi et al. (Proc. Natl. Acad. Sci. U.S.A. 92, 12110–04, 1995) have shown that TGF-β activates a 78-kDa protein (p78) serine/threonine kinase; the p78 kinase was activated only in cells for which TGF-β acts as a growth inhibitory factor. Because of the important functions of kinases such as p78, there is a need in the art to identify new kinases and methods of regulating these new kinases for therapeutic effects.